I’m managing all e-mail addresses in Gmail.

All emails are forwarded to my Gmail account and I send mails by Gmail for these addresses.

Previously, I used Thunderbird and no forwarding was used. But Gmail’s web interface has become so useful, and it is much easier to use it as I can use it with full my settings (especially filters) if only I have a browser.

To add addresses, previously, SMTP server setting was easily by using Gmail’s SMTP server, but recently it was changed a bit.

How to add a mail address to Gmail
Summary

How to add a mail address to Gmail

To add a mail address to Gmail, you need to:

forward the mail from your mail server to Gmail.
add the mail address to Gmail, and enable to choose the address as a sender.

Forward a mail

This should be done in each address’ server side.

Normally mail services, such Yahoo mail, have a setting of mail forwarding. Gmail itself has a forwarding function (SettingsForwarding and POP/IMAP, and Add a forwarding address in Forwarding), therefore you can manage all Gmail accounts in one account easily.

Enable to choose the address as a sender

If you just want to read mails, above forward setting is enough.

If you want to send a mail as other address, you need to add the address to Gmail.

To do this, go SettingsAccount and Import:

and push Add another email address that you own.

Then you will see following screen:

Here, though Treat as an alias. is very confusable, normally I choose not to check it.

If you check it, when you send a mail as outer mail address, the mail will be remain as unread in your inbox.

It seems like to distinguish the address when you set Treat as an alias.. So it seems inverse for me…

Use the ‘Treat as an alias’ setting to manage ‘Send mail as’ account behavior - Google Apps Administrator Help

Anyway, about Specify a different “reply-to” address, normally it is not needed but set if you want to reply as different address.

Then, go Next Step and will see following screen¹:

In the past, there was an option like Send through Gmail (easier to set up) in addition to Send email through your SMTP server.

But the option seems removed around summer 2014.

At first glance, it seems not possible to use Gmail’s SMTP and need each SMTP server of each address…

Set SMTP server manually

But you can use Gmail’s SMTP server by setting it manually.

In above screen, put following information:

SMTP Server: smtp.gmail.com
Port: 587 (or 465)
Username: Your Gmail user name
Password: Your Gmail password (If you are using 2-Step Verification, issue a password for app from My Account.)
TLS or SSL: TLS for 587, SSL for 465

Note: If you have not set 2-Step Verification, you need to allow accesses from less secure apps in Less secure apps - Account settings. (Or you can turn on 2-Step Verification in this opportunity.)

Of course, you can set different SMTP server for each address, and it is sometime better because some mail filters reject if a domain of the address and SMTP server’s domain is different. (Though it becomes less compared to the past.)

But it is easy to use Gmail’s SMTP server especially when you don’t have SMTP server for corresponding address.

Summary

It is very useful to manage all emails in one Gmail account, because you just need a browser to see all of them and use functions with full settings (filters).

There is no easier to set up option to set SMTP server, but you can still use Gmail’s SMTP server if you set it manually. So, you can add even addresses for which you do not have SMTP server.